ICP
Institut de Chimie de Picardie FR CNRS 3085
  • Matinée
    Matinée "modélisation" 5
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    Matinée "modélisation" 4
  • Matinée
    Matinée "modélisation" 3
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    Matinée "modélisation" 2
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    Matinée "modélisation" 1
  • Paulo MARCELO ICP
    Paulo MARCELO ICP
  • Séminaire 3ème Années
    Séminaire 3ème Années
  • Inauguration du HUB de l'énergie
    Inauguration du HUB de l'énergie

Actualités

Straightforward extraction and selective bioconversion of high purity chitin from Bombyx eri larva: Toward an integrated insect biorefinery,

Huet, G.; Hadad, C.; Husson, E.; Laclef, S.; Lambertyn, V.; Araya Farias, M.; Jamali, A.; Courty, M.; Alayoubi, R.; Gosselin, I.; Sarazin, C.; Van Nhien, A. N.

Carbohydr. Polym. 2020, 228, 115382.

Chitins of different purity grades (45%, 89.7% and 93.3%) were efficiently extracted from Bombyx eri larva and fully physico-chemically characterized. Compared to commercially available and extracted α-chitin from shrimp shell, the collected data showed that insect chitins had similar characteristics in terms of crystallographic structures (α-chitin), thermal stability and degree of acetylation (>87%). The major differences lay in the crystallinity indexes (66% vs 75% for shrimp chitin) and in the morphological structures. Furthermore, low ash contents were determined for the insect chitins (1.90% vs 21.73% for shrimp chitin), making this chitin extraction and purification easier, which is highly valuable for an industrial application. Indeed, after only one step (deproteinization), the obtained chitin from Bombyx eri showed higher purity grade than the one extracted from shrimp shells under the same conditions. Insect chitins were then subjected to room temperature ionic liquid (RTIL) pretreatment prior to enzymatic degradation and presented a higher enzymatic digestibility compared to commercial one whatever their purity grade and would be thus a more relevant source for the selective production of N-acetyl-D-glucosamine (899.2 mg/g of chitin-2 steps vs 760 mg/g of chitin com). Moreover, for the first time, the fermentescibility of chitin hydrolysates was demonstrated with Scheffersomyces stipitis used as ethanologenic microorganism.

Glycocluster Tetrahydroxamic Acids Exhibiting Unprecedented Inhibition of Pseudomonas aeruginosa Biofilms,

Taouai, M.; Chakroun, K.; Sommer, R.; Michaud, G.; Giacalone, D.; Ben Maaouia, M. A.; Vallin-Butruille, A.; Mathiron, D.; Abidi, R.; Darbre, T.; Cragg, P. J.; Mullie, C.; Reymond, J. L.; O'Toole, G. A.; Benazza, M.

J. Med. Chem. 2019.

Opportunistic Gram-negative Pseudomonas aeruginosa uses adhesins (e.g., LecA and LecB lectins, type VI pili and flagella) and iron to invade host cells with the formation of a biofilm, a thick barrier that protects bacteria from drugs and host immune system. Hindering iron uptake and disrupting adhesins' function could be a relevant antipseudomonal strategy. To test this hypothesis, we designed an iron-chelating glycocluster incorporating a tetrahydroxamic acid and alpha-l-fucose bearing linker to interfere with both iron uptake and the glycan recognition process involving the LecB lectin. Iron depletion led to increased production of the siderophore pyoverdine by P. aeruginosa to counteract the loss of iron uptake, and strong biofilm inhibition was observed not only with the alpha-l-fucocluster (72%), but also with its alpha-d-manno (84%), and alpha-d-gluco (92%) counterparts used as negative controls. This unprecedented finding suggests that both LecB and biofilm inhibition are closely related to the presence of hydroxamic acid groups.

Nitroxide-Grafted Nanometric Metal Oxides for the Catalytic Oxidation of Sugar,

Omri, M.; Becuwe, M.; Courty, M.; Pourceau, G.; Wadouachi, A.

ACS Applied Nano Materials 2019, 2, 5200-5205.

A new series of ([2,2,6,6-tetramethylpiperidin-1-yl]oxy) (TEMPO) catalysts supported on nanometric metal oxides (TiO2, AlO2, CeO2) and their efficiency for sugar oxidation are herein described. The preparation of such hybrid catalysts was carried out by modification of a metal oxide surface with a monolayer of phosphonic linker bearing a TEMPO radical. All prepared catalysts were carefully characterized by diffuse reflectance Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and transmission electron microscopy. The efficiency of these new hybrid TEMPO supported materials for sugar oxidation was evaluated on methyl α-d-glucoside, as a model carbohydrate. The three hybrid catalysts showed high selectivity, activity, and stability, suggesting a promising potential for rapidly obtaining acid sugar derivatives.

Uncommon Strong Inhibition of α-Glucosidase by Multivalent Glycoclusters built on Cyclodextrins Scaffolds,

Alali, U.; Vallin, A.; Bil, A.; Khanchouche, T.; Mathiron, D.; Przybylski, C.; Beaulieu, R. R.; Kovensky, J.; Benazza, M.; Bonnet, V.

Org. Biomol. Chem. 2019.

The homeostasis disruption of D-glucose causes diabetes, a dramatic world wide chronic disease. The type 1 diabetes is a succesfully treatable form, where the blood D-glucose is regulated by insulin treatement. In contrast the type 2 diabetes , the non Insulin dependent one, is problematic. The control of the D-glucose blood level via intestinal α-D-glucosidase inactivation can be achieved by using competitive inhibitors as iminosugars (e.g. acarbose) or sulfonium sugar derivatives (e.g. salacinol). Recently, an unprecedented result showed that multivalent diamond nanoparticules grafted with unmodified sugars displayed α-glucosidase inhibition at low micromolar concentrations. We describe herein the synthesis of multivalent glycoclusters using cyclodextrines (CDs) as scaffolds and their assessment as inhibithors of α-D-glucosidase. The glycoclusters were efficiently obtained from per-azido α, β and γ-CDs derivatives and propargyl glycosides using click-chemistry under microwave irradiation. The methodology was successfully applied to various protected and non-protected propargylated monosaccharides, including both O- and S- glycosides, giving clear evidences of its versatility. The targeted 6-per-glycosylated CDs were isolated in moderate to excellent yields (30-90 %) by silica gel chromatography. The results showed inhibition of α-glucosidase from Saccharomyces cerevisiae with IC50 values in a 32-132 µM range, lower than that of acarbose (IC50 ~250µM), a well knowm competitive inhibitor used in clinical treatment of type 2 diabetes. Preliminary experiments suggest a mixed-type non-competitive inhibition mode of these new glycoclusters.

First Sustainable Aziridination of Olefins Using Recyclable Copper-Immobilized Magnetic Nanoparticles,

Toumieux, S.; Khodadadi, M.; Pourceau, G.; Becuwe, M.; Wadouachi, A.

Synlett 2019, 30, 563-566.

The first copper-catalyzed aziridination of olefins using recyclable magnetic nanoparticles is described. Magnetic nanoparticles were modified with dopamine and used as a support to coordinate copper. The methodology was optimized with styrene as olefin and using [N-(p-toluenesulfonyl)imino]phenyliodinane (PhI=NTs) as nitrene source. A microwave irradiation decreased the reaction time by 4-fold compared to conventional heating method. The catalyst was recovered by simple magnetic extraction and could be reused successfully up to five times without significant loss of activity. The methodology was applied to a range of different olefins leading to moderate to excellent yields in the formation of the expected aziridine.